num1 = list(input())
num2 = list(input())

#print(num1,num2)
p1 = 0
p2 = 0

result = []

while p1 < len(num1) and p2 < len(num2):
    #print(p1, p2, result)
    if num1[p1] < num2[p2]:
        result.append(num1[p1])
        p1 += 1
    elif num2[p2] < num1[p1]:
        result.append(num2[p2])
        p2 += 1
    else:
        p1_ = p1
        p2_ = p2

        while p1_ < len(num1) and p2_ < len(num2):
            #print(p1,p2,p1_,p2_)
            if num1[p1_] != num2[p2_] :
                break
            p1_ += 1
            p2_ += 1

        min1 = min(num1[p1:p1_+1])
        min2 = min(num2[p2:p2_+1])

        if p1_ == len(num1):
            min1 = min(num1[p1:])
            min2 = min(num2[p2:])
            p1_ = p1
        if p2_ == len(num2):
            min1 = min(num1[p1:])
            min2 = min(num2[p2:])
            p2_ = p2


        if min1 > min2:
            result.append(num2[p2])
            p2 += 1
        elif min1 < min2:
            result.append(num1[p1])
            p1 += 1
        else:
            if len(num1[p1:]) < len(num2[p2:]):
                result.append(num1[p1])
                p1 += 1
            else:
                result.append(num2[p2])
                p2 += 1


if p1 == len(num1):
    result += num2[p2: ]

elif p2 == len(num2):
    result += num1[p1: ]

print("".join(result))